Attachment for sheet metal lock forming machine



Oct. 16, 1956 L. v. PARSONS 2,766,712

ATTACHMENT EOE SHEET METAL Loox FORMING MACHINE Filed Aug. 22, 1952 2 Sheets-Sheet. 1

Lloyd V. Parsons Fig? HTTOBNEYS Oct. 16, 1956 .'v, PARSONS 2,765,712'

ATTACHMENT EOE SHEET METAL Loox EoEMmE-MAQEINE Filed Aug. 22. 1952 2 Sheets- Sheet 2 v INVENToR.

Lloyd V. Parsons ATTACHMENT FOR SHEET METAL LOCK FORMING MACHINE Lloyd V. Parsons, Seattle, Wash.

Application August 22, 1952, Serial No. 305,878

1 Claim. (Cl. 113-58) This invention relates -to sheet metal lock-forming machines. More particularly it has reference to an attachment whereby a present day machine designed to make a specific type of sheet metal lock may be converted for the making of a substantially different type of lock without requiring any major adjustment in rolls or any modification in other parts of the machine.

In sheet metal fabrication work there are numerous types of locks and various means whereby metal sheets may be fastened or joined together. The two types of locks which are most pertinent to the present invention, are known as the Pittsburgh lock and the doubleseam lock or pipe lock. These types of locks will be described and illustrated in detail in this application and the terms double-seam lock and pipe lock will be used synonymously.

It is the principal object of my invention to provide an attachment or replacement parts for a well known present day machine which is primarily adapted to make a Pittsburgh lock so that this machine may be quickly and easily converted to make a double-seam or pipe lock.

Another object of my invention is to provide means whereby a machine for making a Pittsburgh lock can be converted, without requiring modication or adjustment of its forming rolls to make a pipe lock.

A further object of my invention is to provide an attachment whereby a machine, originally designed for making a Pittsburgh lock, will be converted for the making of a pipe lock and wherein the means employed is extremely simple in its construction, inexpensive in its cost of manufacture and which may be easily applied to the machine in a manner of a very few minutes.

Other objects of my invention resides in the detail of construction and combination of parts which will hereinafter be described.

In accomplishing the above mentioned and other objects, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Fig. 1 is a perspective view illustrating the feed gauge bar which comprises a portion of my invention.

Fig. 2 is a perspective view, as seen from the bottom side, of the opening roll bracket which comprises another element of my invention.

Fig. 3 is a perspective view of the element shown in Fig. 2 as seen from the top side.

Fig. 4 is a plan view of a present day sheet metal lock forming machine equipped to make a Pittsburgh sheet metal lock and illustrating a metal sheet being fed through the machine; the feed rolls being shown in dotted lines.

Fig. 5 is a side View of the upper portion of the machine illustrated in plan in Fig. 4.

Fig. 6 is a plan view of the sheet metal lock forming machine shown in Fig. 4 with the attachment of the present invention applied thereto.

Fig. 7 is a side View of the upper portion of the machine illustrated in Fig. 6.

Fig. 8 is an enlarged cross-section, taken on line 8 8 in Fig. 5 and illustrating the Pittsburgh sheet metal lock as produced by passing the metal sheet -through the machine.

Fig. 9 is an enlarged cross-section, taken on line 9 9 in Fig. 5 and illustrating the opening roll bracket and the sheet metal with the Pittsburgh lock formed therein.

Fig. 10 is an enlarged cross-section taken on line 10-10 in Fig. 7 and illustrating a double-seam lock, or pipe lock, which is formed by the present attachments as applied to the machine.

Fig. 11 is an enlarged cross-section, taken on line 11-11 in Fig. 7, showing the opening roll bracketand the sheet metal lock formed in the sheet metal material.

Fig. 12 is a cross-section taken on line 12-12 in Fig. 1.

To manufacture sheet metal pipes and other sheet metal items, requiring the joining of the ends or edges of sheets together, it is the common practice to form longitudinal edges of the sheet metal, and `then to bend the sheet into a rectangular, square or circular tube and interengage the hooks and crimp them in secure, interlocking relationship. It is the common practice of today to form the interlocking hooks or flanges of the edge portions of the metal sheet through what is commonly called a lock forming machine. Such a machine comprises a series of rollers which progressively bend and crimp the edge portion of the sheet metal in passing, to form the desired hook. Due to the complexity of such machines, in the past it has required separate sets of rolls to form each specific type of lock. In other Words, it has not been possible to form a double-seam lock in a machine which is equipped with rollers to form a Pittsburgh lock, and vice versa. Present day machines equipped with rollers to make the double-seam lock are not capable of forming a Pittsburgh lock. There are machines available which permit lthe forming of the. different locks on the same machine but to do this they must employ different sets of rollers for forming the different locks. Machines with a multiplicity of sets of rollers are substantially more expensive than those with one set of forming rolls.

By employing the devices `comprised in my invention, I am able to convert a machine that is equipped with rolls, designed to form a Pittsburgh lock, for the making of a double-seam lock using the same set of rolls. The present attachment is extremely simple and it can be readily applied to machines already in use by merely removing four bolts to apply the attachment, then replacing them to secure it. It is not required that the rolls be adjusted or altered in any way.

Referring more in detail to the drawings- In Figs. 1, 2 andl 3, I have illustrated the component parts which comprise the attachments whereby I am able to modify a Pittsburgh lock forming machine for the making of a double-seam o-r pipe lock.

These component parts comprise the feed gauge bar 10 best shown in Fig. 1 as being a ilat, rectangular bar formed with true, straight longitudinal side walls 10a, and having two holes 10b formed therethrough to receive securing bolts as presently explained. It is to be noted that these holes are equally spaced from the ends of the bar but are located closer to one longitudinal edge of the bar than the other for a reason present apparent.

Another of the component parts which comprise the attachment is the opening roll bracket 11, illustrated in Figs. 2. and 3. This bracket is a ilat rectangular bar of metal, such as steel, with bolt receiving holes 11a formed therethrough. Secured to one end of the bar, against one face thereof, and at a right angle to the bar, is an arm 15; this being secured by a bolt 16 applied therethrough as seen best in Fig. 2. At its outer end, this arm is formed by means of a rounded bend with a backturned hook 17 having a dat under surface 17x at an angle of about 30 to the plane of the face of the bar and a top surface 17b in a plane that is parallel to Vthe plane of the face of the bar. The hook 17 thus terminates in a direction transversely of the hook in a thin edge 17e as best shown in Fig. ll.

One longitudinal edge of the hook, herein designated the forward edge, is beveled or tapered to a thin edge 17a, and this gradually increases to full thickness across the hook.

Mounted on the arm 15, relatively close to the transverse edge 17e of the hook 17, is a pin 2t) which serves as a guide and retaining pin as later explained.

In Figs. 4 and 5, I have illustrated the sheet metal lock forming machine to which the present attachment is to be applied. The machine is designated in its entirety by reference numeral 30, as equipped to form a Pittsburgh lock comprises a bed 31 with a flat top surface, the feed gauge bar 32 and an opening roll bracket 33. In these views, I have illustrated a piece of sheet metal 35, as being fed through the machine in a lock hook forming process. The hook is formed along the longitudinal edge of the sheet by the set of forming rolls. The forming rolls illustrated comprise the upper rolls 41 and the lower rolls 42. These rolls have their edges beveled at various angles so that as the metal sheet is fed progressively through the coacting rolls, its edge portion is bent and crimped to form the Pittsburgh sheet metal lock illustrated in Figs. 8 and 9. The particular construction and function of the forming rolls is not a feature of my invention, and therefore the exact purpose or function of the respective pairs of upper or lower rolls will not be herein described. The rolls are driven by an electric motor through a belt or gear drive not herein shown and the operator aligns and guides the sheet material against the feed gauge bar 32 and causes the material to be fed into the machine. The revolving rolls draw the material through the machine and form a specific lock, in this instance, the Pittsburgh lock.

To adapt the machine illustrated in Figs. 4 and 5 to make a double-seam or pipe lock, I employ the feed gauge bar illustrated in Fig. 1 and the opening roll bracket illustrated in Figs. 2 and 3; these being applied as shown in Figs. 6 and 7. In these views the feed gauge bar 32, as seen in Figs. 4 and 5, has been replaced by the bar 10 of Fig. l; this replacement being accomplished by first removing the securing bolts 4S-4S which are threaded into a plate (not shown) on the top surface of the machine. The bar is applied and secured by the same bolts applied in the same way as previously used. Though I have illustrated the use of two sizes of feed gauge bars in Figs. 4 and 6, if desired, a single, reversible bar may be used by merely locating the holes to one side of the longitudinal center line a distance sufficient to accomplish the desired guiding of the sheet material. It will be noted by reference to Fig. 6 that the feed gauge bar 10 is so applied that the part of greater width relative to the longitudinal line through the bolt holes there in will be extended toward the longitudinal line of the forming rolls. lt will be noted by comparing the location of the guiding edge of bar 32 in Fig. 4 with the location of the guiding edge of bar 10 in Fig. 6, that the latter extends a substantially greater distance from the line 5t) than does the bar 32. Thus when the sheet material is fed into the machine of Fig 6, the forming rolls will act on a strip of material of lesser width than that acted on in feeding the sheet of metal through the machine of Fig. 4. The opening roll bracket 11 is applied and secured to the machine by the bolts 46-46 and it replaces the feed roll bracket 33 illustrated in Figs` 4 and 5. The bracket 11 is applied with the pin 20 and hook portion 17 extending upwardly as is illustrated in Figs. 3 and 1l. No additional adjustment or alteration of the machine is required as the opening roll bracket 11 is merely a substitute for the opening roll bracket 33, and its position is exactly the same.

Thus by merely substituting the present feed gauge bar 1() and the opening roll bracket 11, I have converted the sheet metal lock forming machine, which is primarily adapted to making Pittsburgh locks so that in a like manner of operation it will produce a double-seam or pipe lock. For this operation the straight longitudinal edge of the metal sheet 60 is aligned against the feed gauge bar 10 as illustrated in Fig. 6 and is fed between the hook forming rolls of the machine to produce a single overlapping bend illustrated in Figs. l0 and ll.

The sheet metal lock illustrated in Figs. 8, 9, 10 and ll are enlarged views for purposes of illustration and are not to be compared to the size of the machine or to the size of the feed gauge bars or opening roll brackets illustrated in Figs. l, 2 and 3.

With reference to the showing of the Pittsburgh lock in Figs. 8 and 9, the sheet metal is formed, parallel with the edge of the sheet with a at, triple fold, comprising a top layer 35a, a middle layer 35b and a bottom layer 35C; the latter being in the plane of the metal sheet in which the fold is formed. In the operation, the fold is opened, as in Fig. 8, by the opening roll 33 as shown in Fig. 9, providing the open longitudinal channel into which the opposite end hook of the sheet can be received, as well understood in the art.

In Figs. l0 and ll, I have illustrated the double-seam or pipe lock and the means for opening the pipe lock for interlocking the opposite edges of a piece of sheet metal formed into round or circular form. To form the double seam lock, the sheet metal 35 is fed through the machine by engaging its edge against the feed gauge bar 10 and causing the metal to be fed through the pairs of coacting forming rolls. The purpose of my feed gauge bar is to prevent or substantially reduce the width of the strip of material that is fed through the rolls; this width being reduced to such extent that the rolls are unable to form the second and third bend which comprises the lower layer and outer end portion of the Pittsburgh lock. Thus with my attachments, the sheet metal is then formed to provide t-he single bend at 35e, to position the intermediate portion 35b which underlies the top portion 35a. When the material being fed through the machine reaches my novel fold opening means 17 on the opening roll bracket 11, the material comprising the top portion 35a and the underlying portion 3517 are caused to be separated in a V joint as illustrated in Figs. l() and 1l. The pin 20 is provided as a means of keeping the sheet metal in a straight and true position to insure that it will engage the hooked portion 17a of the opening roll bracket. Thus with substantially the same machine, I am able to form the Pittsburgh lock and then by minor adjustments and an interchange of parts, as previously explained, I can also form a double-seam lock, and the machine can be changed from one lock to another in a relatively short period of time.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is:

A sheet metal lock forming machine including a bed having a at upper surface for supporting a sheet of material to be bent, a single sexies of forming rolls rotatably mounted on horizontal axes in spaced relation along the bed, a gauge bar adjacent the receiving end of said series of rolls against which one edge of a sheet of material to be bent is engagea'ble to guide the sheet to and through the rolls, an opening member mounted on the bed and cooperable with the last roll of said series to spread the bent over marginal edge portion of the sheet away from the main body thereof, said opening member including an elongate arm disposed below the upper surface of said bed and in spaced relation below the axis of said last roll, said arm terminating at one end in a back turned hook overlying the arm to project above the l upper Surface of said bed and disposed directly below such last roll, the major portion of said arm extending outwardly from the line of fold upon which said material is bent, and an upstanding pin rigid with said arm spaced from the end of said hook outwardly of said line of fold to dene a conning space between said end of the hook and the pin to retain the bent portion of the sheet on the hook.

References Cited in the tile of this patent UNITED STATES PATENTS Schlafiy Sept. 24, 1901 Lockwood Mar. 15, 1904 Little May 23, 1905 Jensen Dec. 9, 1941 Jensen May 19, 1942 

